OBJECTIVE It is still not clarified whether spasticity contributes to impairments of gait function. Here we compared biomechanical measures of muscle weakness and stiffness of ankle muscles to impairments of gait function in adults with cerebral palsy (CP). METHODS Twenty-four adults with CP (mean age 34.3, range 18-57 years) and fifteen healthy age-matched controls were biomechanically measu...

Our overall objectives were to examine the role of peripheral afferents from the ankle in modulating stretch reflexes during imposed walking movements and to assess the mechanical consequences of this reflex activity. Specifically we sought to define the changes in the electromyographic (EMG) and mechanical responses to a stretch as a function of the phase of the step cycle. We recorded the ank...

 Abstract Background: Several studies have examined the reflex response of ankle musculature to sudden inversion in noninjured and injured subjects. To date, there have been no studies to determine the effect of versatile degrees & conditions of perturbation on the ankle musculature latency. The purpose of this study was to measure and determine whether there was a difference in ankle musculatu...

Background and Objectives: Diabetes mellitus is one of the major health problems, and one of its commonest complications is peripheral neuropathy. The aim of this study is to evaluate four standard simple screening tests (10-g Semmes-Weinstein monofilament examination {SWME}, vibration sensation by a 128Hz tuning fork, superficial pain test and ankle reflex) for detection of neuropathy using th...

The rapid decrease in firing of load-sensitive group Ib muscle afferents during unloading may be particularly important in triggering the swing phase of gait. However, it still remains unclear whether load-sensitive muscle afferents modulate reflex activity in human spinal cord injury (SCI), as suggested by studies in the cat. The right hip of 12 individuals with chronic SCI was subjected to ra...

Dynamic joint stiffness is a dynamic, nonlinear relationship between the position of a joint and the torque acting about it, which can be used to describe the biomechanics of the joint and associated limb(s). This paper models and quantifies changes in ankle dynamic stiffness and its individual elements, intrinsic and reflex stiffness, in healthy human subjects during isometric, time-varying (T...

Abstract The effects of long-term Functional Electrical Stimulation (FES) assisted walking on ankle dynamic stiffness were examined in spinal cord injured (SCI) subjects with incomplete motor function loss. A parallelcascade system identification method was used to identify intrinsic and reflex contributions to dynamic ankle stiffness at different positions with subjects instructed to remain re...

We investigated differences in corticospinal and spinal control between discrete and rhythmic ankle movements. Motor evoked potentials (MEPs) in the tibialis anterior and soleus muscles and soleus H-reflex were elicited in the middle of the plantar flexion phase during discrete ankle movement or in the initial or later cycles of rhythmic ankle movement. The H-reflex was evoked at an intensity e...

Many ankle injuries are said to occur when athletes are in a fatigued state; therefore, studies investigating the role that fatigue plays in ankle injuries are warranted. Furthermore, the contributions of the stretch reflex in countering the injury mechanism are still unclear. We hypothesized that (1) fatigue would impair the reflex response, (2) there would be no differences between genders, (...

The influence of motoneuron pool properties on the stability of the stretch reflex at the ankle in subjects with spinal cord injury was tested using a comprehensive model of the reflex pathway. This model included the passive and active components of the triceps surae muscles, muscle spindles, neural transport delays, limb mechanical properties, and a lumped parameter model of the motoneuron po...